<template>
  <div class="login_container">
    <div class="login_box">
      <!--头像-->
      <div class="avatar_box">
        <img src="../assets/logo.png" alt="">
      </div>
      <!--表单区-->
      <el-form label-width="0px" class="login_form" :model="loginForm" :rules="loginFormRules" ref="loginFormRef">
        <!--用户名-->
        <el-form-item prop="username">
          <el-input prefix-icon="iconfont icon-user" v-model="loginForm.username"></el-input>
        </el-form-item>
        <!--密码-->
        <el-form-item prop="password">
          <el-input prefix-icon="iconfont icon-3702mima" v-model="loginForm.password" type="password"></el-input>
        </el-form-item>
        <!--按钮-->
        <el-form-item class="btns">
          <el-button type="primary" @click="login">登录</el-button>
          <el-button type="info" @click="resetLoginForm">重置</el-button>
        </el-form-item>
      </el-form>
    </div>
  </div>
</template>

<script>
export default {
  name: "Login",
  data() {
    return {
      loginForm: {
        username: 'admin',
        password: '123456'
      },
      loginFormRules: {
        username: [
          {required: true, message: '请输入登录名称', trigger: 'blur'},
          {min: 2, max: 10, message: '长度在 2 到 10 个字符', trigger: 'blur'}
        ],
        password: [
          {required: true, message: '请输入登录密码', trigger: 'blur'},
          {min: 3, max: 10, message: '长度在 2 到 15 个字符', trigger: 'blur'}
        ]
      }
    }
  },
  methods: {
    resetLoginForm() {
      this.$refs.loginFormRef.resetFields()
    },
    //登录的预验证
    login() {
      this.$refs.loginFormRef.validate(async (valid) => {
        if (!valid) return;
        //如果某个方法的返回值是promise，可以用async，await简化promise操作,await只能用在async修饰的方法中
        const {data: res} = await this.$http.post('login', this.loginForm)      //返回promise
        if (res.meta.status !== 200) return this.$message.error('登录失败')
        this.$message.success('登录成功')

        // 1. 将登录成功之后的 token,保存到客户端的 sessionStorage(会话机制/只在当前页面生效)中 localStorage(持久话机制/关闭页面也不会忘记数据)
        // 1.1 项目中除了登录之外的API接口,必须在登录之后才能访问
        // 1.2 token 只应在当前网站打开期间生效, 所以将 token 保存在 sessionStorage中
        window.sessionStorage.setItem('token', res.data.token)
        // 2. 通过编程式路由导航跳转到后台主页,路由地址是 /home
        this.$router.push('/home')
      })
    }
  }
}
</script>

<style lang="less" scoped>
.login_container {
  background-color: #2b4b6b;
  height: 100%;
}

.login_box {
  width: 450px;
  height: 300px;
  background: #fff;
  border-radius: 3px;
  position: absolute;
  /*left: 50%;*/
  /*top: 50%;*/
  /*transform: translate(-50%, -50%);*/
  left: 0;
  right: 0;
  top: 0;
  bottom: 0;
  margin: auto; /*居中，两种方法都可以*/

  .avatar_box {
    height: 130px;
    width: 130px;
    border: 1px solid #eee;
    border-radius: 50%;
    padding: 10px;
    box-shadow: 0 0 10px #ddd;
    position: absolute;
    /*绝对定位使盒子居中*/
    left: 50%;
    //margin-left: -75px;
    transform: translate(-50%, -50%);
    background-color: #fff;

    img {
      width: 100%;
      height: 100%;
      border-radius: 50%;
      background-color: #eee;
    }
  }
}

.login_form {
  position: absolute;
  bottom: 0;
  /**/
  width: 100%;
  padding: 0 20px;
  box-sizing: border-box; /*元素的总高度和宽度包含内边距和边框*/
}

.btns {
  display: flex;
  justify-content: flex-end;
}
</style>